1. Three sets of oxygen plasma torches and power units were purchased and a control unit which enables instantaneous transition from a transfer mode to a nontrnasfer mode of a torch operation were manufactured.2. A simple furnace with fixed torches were manufactured for preliminary melting experiments through which suitable conditions for melting were sought and data necessary for manufacturing a final furnace.3. Through the melting experiments of zirconia alloys using the preliminary furnace, the following results were obtained : (1) Yttria doped zirconia could be melted without reduction under the oxygen plasma arc. (2) Although ceria doped zirconia resulted in dendrite structure through the solidification, this could be removed by homogenizing heating just below the melting temperature. (3) Because of the thin arc of the oxygen plasma, heating of a spcimen above 10mm size could not be heated uniformly.4. Based on these data, a furnace with a rotating hearth with up-down motion was manufactured.5.予備実験の結果を参考にして最終目的炉を作成した.この炉対は試料の均熱を図るためハ-スの連続回転機構と上下機構を備えている.これらの機構を備えることにより,溶解効率の改善と凝固後の均質化処理および高温加熱処理が可能になることが期待される.